GN: Update heap stubs for android

Source/platform/heap/BUILD.gn

Index: Source/platform/heap/BUILD.gn
diff --git a/Source/platform/heap/BUILD.gn b/Source/platform/heap/BUILD.gn
index c7185bda78f615f3d85f7c774812567639e77c3c..a745f13d779437e06a91d7429f728f12f90e04ba 100644
--- a/Source/platform/heap/BUILD.gn
+++ b/Source/platform/heap/BUILD.gn
@@ -16,19 +16,11 @@ source_set("heap") {
     "Visitor.cpp",
     "Visitor.h",
   ]
-  if (cpu_arch == "x86" || cpu_arch == "x64") {
-    sources += [ "asm/SaveRegisters_x86.asm" ]
-  } else if (cpu_arch == "arm") {
-    sources += [ "asm/SaveRegisters_arm.S" ]
-  } else if (cpu_arch == "arm64") {
-    sources += [ "asm/SaveRegisters_arm64.S" ]
-  } else if (cpu_arch == "mipsel") {
-    sources += [ "asm/SaveRegisters_mips.S" ]
-  }
 
   configs += [ "//third_party/WebKit/Source:config" ]
 
   deps = [
+    "//third_party/WebKit/Source/platform/heap/asm",
     "//third_party/icu",
   ]
 }